The leaning tower of Pisa is 58.36 meters high from the foundation to the top of the tower and 55 meters high from the ground to the top of the tower. The wall of the bell tower is 4.09 meters wide on the ground and 2.48 meters wide on the top of the tower, with a total weight of about 14453 tons, and its center of gravity is 22.6 meters above the foundation. The circular foundation covers an area of 285 square meters and the average ground pressure is 497 kPa. At present, the slope is about 10%, that is, 5.5 degrees, 2.3 meters away from the outer edge of the foundation, and the top floor protrudes 4.5 meters.
The leaning tower of Pisa is the symbol of Pisa. 1987, because of its great influence on Italian architectural art from1century to14th century, it was selected as a world heritage site by UNESCO together with the adjacent cathedrals, baptisms and cemeteries.
The construction of the bell tower of Pisa Cathedral began in August of 1 173. This project was interrupted twice and lasted for a long time, which took about 200 years to complete. Its designer is still unknown.
The inscription found on the right wall of the entrance of the bell tower records the time when the bell tower began to be built: "MCL XXIV. Campanile hocfuit Fundatum mense Augusti ",translated as" This bell tower was laid in August of AD 1 174 "(Note: it was actually August of 65438+01August of 73. This year has also appeared in historical archives and contemporary chronicles many times.
The circular design of the bell tower is considered to correspond to the reflection of the cathedral building on the side, so it deliberately imitates the curve design of the semi-circular back hall of the church. More importantly, the bell tower is consistent with the emphasis on circular structure in the square, especially after the completion of the grand circular Baptist church, the whole square is more like the modern version of Anastasi in Jerusalem. This design is derived from classic ancient architecture.
The decorative style of the bell tower inherits the classic works of cathedral and Baptist church. This wall is made of marble or limestone and divided into two kinds of white belts. The arch with semi-exposed square columns, the carved gate in the arcade, the rhombic lattice flat top and the wall above the arcade form a strong contrast between the bright side and the dark side, giving people the illusion that the columns in the bell tower are quite heavy. There is a visual continuity between cathedral, Baptist church and bell tower.
In the past, people used to think that the bell tower was deliberately designed to tilt, but now people clearly know that this is not the case. As the bell tower of Pisa Cathedral, the design of 1 173 was erected vertically when it was built on August 9. The original design is 8 floors with a height of 54.8 meters. Its unique white flashing medieval style building will be one of the most noteworthy bell towers in Europe, even if it does not tilt later.
1 185, when the bell tower was built to the fourth floor, it was found that the bell tower had tilted to the southeast due to uneven foundation and soft soil, and the project was suspended. During the period of 1 198, the existence of the bell tower was recorded, indicating that although the bell tower was tilted, at least one bell was hung, realizing its original intention as a bell tower.
123 1 year, the project continued, and the use of marble in the bell tower was recorded for the first time. The builder has taken various measures to correct the inclination, and deliberately built the upper floor of the bell tower to tilt in the opposite direction to compensate for the shift of the center of gravity that has occurred.
When 1278 goes to the seventh floor, the tower is no longer straight, but concave. The project is suspended again.
1360, after almost a century of stagnation, the bell tower began its last sprint and made the last important modification.
1372 built the top floor of the clock, so the whole building was completed and the tower tilted to the southeast. There are seven clocks in the 54-meter-high eight-story bell tower, but it has not been knocked off because it is in danger of collapse at any time.
Professor Piroddi, a medieval historian in Pisa, believes that every Shi Zhuan in the tower is a masterpiece of stone carving, and the bonding between Shi Zhuan and stone bricks is very clever, which effectively prevents the tower from breaking due to inclination and becomes a factor that the leaning tower will not fall down.
According to legend, Galileo, an Italian physicist born in Pisa, observed the swing of a copper chandelier in Pisa Cathedral when he was 19 years old, thus discovering the isochronous law of small swing, which was a prelude to his dynamic research.
1590, Galileo made a free fall experiment on the leaning tower of Pisa, which overthrew Aristotle's previous view that heavy objects would fall to the ground first, and the speed of falling was directly proportional to the mass.